You guys are scaring me. I may boycott the film if either Johnny Depp, John Travolta or Nic Cage are added to the project. I don't ever want to hear Depp sing again, John Travolta's not even a good actor and Nic Cage is on my list of people I'm tired of seeing (oh how he's fallen since Adaptation and Leaving Las Vegas).
Mark Ruffalo would be interesting. They can give him makeup to make him look older, like in Zodiac, but I think his personality seems very much an "Old soul". And Cannavale is a decent actor, though definitely was the weak link in The Station Agent.
"Any society that would give up a little liberty to gain a little security will deserve neither and lose both." - Benjamin Franklin